Biology Tests and Procedures | Biology Junction



| |Volume of an Irregular-shaped Object |[pic] |

| | Introduction |

| |The word mass is used to tell how much matter there is in something. Matter is anything you can touch physically. An electronic scale or triple beam |

| |balance can be used to tell the mass of an object. Volume is a measure of how much space an object occupies. When measuring the volume of a liquid, a |

| |graduated cylinder can be used.   Measurement is the collection of quantitative data (numbers). Measurements are not only numbers. They must always |

| |contain a unit of measurement. In the Metric System, the gram (g) is the basic unit of measurement for mass. The basic unit of measurement for the |

| |volume of liquids is the milliliter (ml). The density of an object can be determined by dividing the mass by the volume (D = M/V). From a density |

| |calculation, we may tell whether a substance will float or sink in another liquid. A less dense substance will float on one that is denser. An example |

| |is oil floating on water. Oil is less dense than the water.   |

| |For solids that have an irregular shape, the displacement method must be used to determine their volume. When using the displacement method, you must |

| |first measure the starting volume of the liquid. Then add the object and record the change in volume. This gives the volume of the irregularly-shaped |

| |object.   |

| |Hypothesis |

| |The density of objects can be determined by a method known as water displacement.   |

| |Materials |

| |Triple beam or electronic balance |

| |100 ml graduated cylinder |

| |3 irregularly shaped objects |

| |calculator |

| |pencil   |

| |Procedure |

| |Obtain 3 irregularly shaped objects that will sink in water. |

| |Estimate the mass & volume of each object. Record this on table 1. |

| |Use a triple beam balance or electronic scale to determine the mass in grams of each object. Record this on table 1. |

| |Fill a graduated cylinder halfway with tapwater. |

| |Measure & record the volume of the water in the graduated cylinder. READ THE MENISCUS!   |

| |Place one of the objects into the graduated cylinder, and measure and record the new volume. |

| |Subtract the initial volume from the final volume. The difference is the volume of the object. |

| |Record the difference in data table 1. |

| |Repeat steps 4 - 8 for the other three objects. |

| |To determine the density of each object, divide the actual mass of each object by its volume (determined by water displacement). |

| |Record the densities in data table 1. |

| |Results & Data |

| | Data Table 1 |

| |Object |

| |Estimated Mass |

| |(g) |

| |Estimated Volume |

| |(ml) |

| |Actual Mass |

| |(g) |

| |Volume of H2O in graduated cylinder |

| |(ml) |

| |Volume of H2O and object in graduated cylinder |

| |(ml) |

| |Object's Volume |

| |(Subtract Column 5 from Column 6) |

| |(ml) |

| |Density |

| |D=m/V |

| |(Divide Column 4 by Column 7) |

| |(g/ml) |

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| |How did you determine the object's: |

| |      A. mass? |

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| |      B. Volume? |

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| |      C. density? |

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| |Objects will sink if they are denser than water. Explain why ships made of steel float instead of sinking since steel is denser than water. |

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